This invention relates to a method for preparing dialkyl dithiodialkanoates. In one of its aspects this invention relates to a process for recycling hydrocarbon solvent in a reaction process without purification or other treatment of the solvent. In yet another aspect the invention relates to a method for neutralizing acidic by-products in the production of dialkyl dithiodialkanoates.
In addition to pigments and fillers, commercial paints are composed of several additives which enhance performance and prolong the life of the painted surface. Among these additives are fungicides. Paints are attacked in both the liquid and dry state by various microorganisms (bacteria, fungi). In aqueous paints bacterial fermentation results in odoriferous compounds, loss of viscosity, and popping of can lids due to carbon dioxide formation. Bacteria or fungi most often attack painted surfaces under damp and humid conditions. Some paint pigments such as zinc, copper, lead, and chromium oxides are themselves fungicidal to a certain degree as are alkaline compounds used in paint such as calcium carbonate and barium metaborate. However, in most cases where fungal attack is likely to be severe, additional fungicides sometimes referred to as mildewcides are added. The most widely used paint preservatives are phenylmercuric salts of various organic acids such as phenylmercuric acetate (used in latex water-based paints), phenylmercuric oleate (used in oil-based paints), phenylmercuric propionate (used in both oil and water-based paints), and some chlorinated derivatives. However, because of the environmental hazards associated with mercuric and chlorinated compounds, there exists a need for fungicides based on non-mercuric, non-halogenated products. Among the products being used as fungicides in paints are sulfur-containing organic compounds, such as dialkyl dithiodialkanoates, many of which have gained wide acceptance as control agents in other areas such as agriculture, underground wire installation, bathroom caulking, etc.
It is therefore an object of this invention to provide a method for producing sulfur-containing organic compounds useful as fungicides and mildewcides. It is another object of this invention to provide a method for producing dialkyl dithiodialkanoates. It is still another object of this invention to provide a method for reacting mercaptoalkyl ester with a halogen in which a hydrocarbon solvent can be recycled through the process without further treatment or purification.
Other aspects, objects and various advantages of this invention will become apparent upon reading the specification and appended claims.